chore: remove seaslog extension due to PHP 8.1+ incompatibility

Remove seaslog extension from all PHP versions as it fails to compile on PHP 8.1+ due to Zend Engine API changes. The extension (v2.2.0, last updated January 2021) claims PHP 8 support but only works with PHP 8.0.

Compilation error: incompatible pointer types in ErrorHook.c
- zend_error_cb signature changed in PHP 8.1+
- Extension appears abandoned (no updates in 4 years)

Changes:
- Removed all seaslog Dockerfiles (PHP 8.1, 8.2, 8.3)
- Removed seaslog entry from README.md

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: fox91

8.1/alpine3.22/pecl_seaslog/Dockerfile

@@ -49,7 +49,6 @@ Extension | PHP `8.1` `bookworm` | PHP `8.1` `alpine3.22` | PHP `8.2` `bookworm`
 [`phpiredis`](https://github.com/nrk/phpiredis) | `(1.0.1)` [:whale:](8.1/bookworm/phpiredis/Dockerfile) | `(1.1.x)` [:whale:](8.1/alpine3.22/phpiredis/Dockerfile) | `(1.0.1)` [:whale:](8.2/bookworm/phpiredis/Dockerfile) | `(1.1.x)` [:whale:](8.2/alpine3.22/phpiredis/Dockerfile) | `(1.0.1)` [:whale:](8.3/bookworm/phpiredis/Dockerfile) | `(1.1.x)` [:whale:](8.3/alpine3.22/phpiredis/Dockerfile) | `(1.0.1)` [:whale:](8.4/bookworm/phpiredis/Dockerfile) | `(1.1.x)` [:whale:](8.4/alpine3.22/phpiredis/Dockerfile)
 [`protobuf`](https://pecl.php.net/package/protobuf) _PECL_ | `(4.33.1)` [:whale:](8.1/bookworm/pecl_protobuf/Dockerfile) | `(4.33.1)` [:whale:](8.1/alpine3.22/pecl_protobuf/Dockerfile) | `(4.33.1)` [:whale:](8.2/bookworm/pecl_protobuf/Dockerfile) | `(4.33.1)` [:whale:](8.2/alpine3.22/pecl_protobuf/Dockerfile) | `(4.33.1)` [:whale:](8.3/bookworm/pecl_protobuf/Dockerfile) | `(4.33.1)` [:whale:](8.3/alpine3.22/pecl_protobuf/Dockerfile) | `(4.33.1)` [:whale:](8.4/bookworm/pecl_protobuf/Dockerfile) | `(4.33.1)` [:whale:](8.4/alpine3.22/pecl_protobuf/Dockerfile)
 [`redis`](https://pecl.php.net/package/redis) _PECL_ | `(6.3.0)` [:whale:](8.1/bookworm/pecl_redis/Dockerfile) | `(6.3.0)` [:whale:](8.1/alpine3.22/pecl_redis/Dockerfile) | `(6.3.0)` [:whale:](8.2/bookworm/pecl_redis/Dockerfile) | `(6.3.0)` [:whale:](8.2/alpine3.22/pecl_redis/Dockerfile) | `(6.3.0)` [:whale:](8.3/bookworm/pecl_redis/Dockerfile) | `(6.3.0)` [:whale:](8.3/alpine3.22/pecl_redis/Dockerfile) | `(6.3.0)` [:whale:](8.4/bookworm/pecl_redis/Dockerfile) | `(6.3.0)` [:whale:](8.4/alpine3.22/pecl_redis/Dockerfile)
-[`seaslog`](https://pecl.php.net/package/seaslog) _PECL_ | `(2.2.0)` [:whale:](8.1/bookworm/pecl_seaslog/Dockerfile) | `(2.2.0)` [:whale:](8.1/alpine3.22/pecl_seaslog/Dockerfile) | `(2.2.0)` [:whale:](8.2/bookworm/pecl_seaslog/Dockerfile) | `(2.2.0)` [:whale:](8.2/alpine3.22/pecl_seaslog/Dockerfile) | `(2.2.0)` [:whale:](8.3/bookworm/pecl_seaslog/Dockerfile) | `(2.2.0)` [:whale:](8.3/alpine3.22/pecl_seaslog/Dockerfile) | ✗ | ✗
 [`snmp`](https://php.net/snmp) | [:whale:](8.1/bookworm/snmp/Dockerfile) | [:whale:](8.1/alpine3.22/snmp/Dockerfile) | [:whale:](8.2/bookworm/snmp/Dockerfile) | [:whale:](8.2/alpine3.22/snmp/Dockerfile) | [:whale:](8.3/bookworm/snmp/Dockerfile) | [:whale:](8.3/alpine3.22/snmp/Dockerfile) | [:whale:](8.4/bookworm/snmp/Dockerfile) | [:whale:](8.4/alpine3.22/snmp/Dockerfile)
 [`soap`](https://php.net/soap) | [:whale:](8.1/bookworm/soap/Dockerfile) | [:whale:](8.1/alpine3.22/soap/Dockerfile) | [:whale:](8.2/bookworm/soap/Dockerfile) | [:whale:](8.2/alpine3.22/soap/Dockerfile) | [:whale:](8.3/bookworm/soap/Dockerfile) | [:whale:](8.3/alpine3.22/soap/Dockerfile) | [:whale:](8.4/bookworm/soap/Dockerfile) | [:whale:](8.4/alpine3.22/soap/Dockerfile)
 [`sockets`](https://php.net/sockets) | [:whale:](8.1/bookworm/sockets/Dockerfile) | [:whale:](8.1/alpine3.22/sockets/Dockerfile) | [:whale:](8.2/bookworm/sockets/Dockerfile) | [:whale:](8.2/alpine3.22/sockets/Dockerfile) | [:whale:](8.3/bookworm/sockets/Dockerfile) | [:whale:](8.3/alpine3.22/sockets/Dockerfile) | [:whale:](8.4/bookworm/sockets/Dockerfile) | [:whale:](8.4/alpine3.22/sockets/Dockerfile)